Again Mark shrugged.

“We trust you to get us through,” Gary said, smiling now. He was twenty-one.

“I’m not going,” Mark said.

Gary and his brothers exchanged glances. Gary said, “What do you mean? That’s your job.”

Mark shook his head. “My job was to find out if the cities are there, if anything’s left in them. I know I reached them by water. I don’t know if they can be reached on foot. I know there’s been radioactivity, and I’m going back to the valley to report that.”

Gary stood up and began to roll the map they had been using to mark the swamps, the changed coastline, the marsh that had been the intercoastal waterway. Not looking directly at Mark, he said, “Everyone in this expedition is under my command, you know. Everyone.”

Mark didn’t move.

“I order you to go with us,” Gary said, and now he looked at Mark.

Mark shook his head. “You won’t make it there and back before the weather changes,” he said. “You and your brothers don’t know anything about the forests. You’ll have the same trouble the early expeditions had in coming to Washington. And the boys can’t do anything without someone to tell them what to do. What if all the stuff in Philadelphia is radioactive? If you bring it back, you’ll kill everyone with it. I’m going back to the valley.”

“You’re going to take orders just like everyone else!” Gary shouted. “Keep him here!” He motioned to two of his brothers, and they hurried from the room. The other three remained with Mark, who was still sitting cross-legged on the floor where he had been from the beginning of the meeting.

In a few minutes Gary returned; he carried several long strips of birch bark. Now Mark stood up and reached for the bark. It was from his canoe.

Gary thrust the scraps at him. “Now you understand, I hope. We leave in the morning. You’d better get some rest.”

Wordlessly Mark left them. He went to the river and examined the ruined boat. Afterward he built a small fire, and when it was burning brightly he put one end of the boat in the flames, and as it burned he pushed it forward until it was totally consumed.

The next morning when the boys assembled to start the trek to Philadelphia, Mark was not among them. His pack was gone, he could not be found. Gary and his brothers consulted angrily and decided to start without him. They had good maps that Mark himself had corrected. The boys were all well trained. There was no reason to feel dependent on a fourteen-year-old. They started off, but there was a pall over them now.

Mark watched from a distance, and throughout the day he kept them in sight. When they camped that night, their first night in the open forest, he was in a tree nearby.

The boys were all right, he thought with satisfaction. As long as their groups were not separated, they would be all right. But the Gary brothers were clearly nervous. They started at noises.

He waited until the camp was still, and then, high in a tree where he could look down on them without being seen, he began to moan. At first no one paid any attention to the noises he made, but presently Gary and his brothers began to peer anxiously at the woods, at one another. Mark moaned louder. The boys were stirring now. Most of them had been asleep when he started. Now there was a restless movement among them.

“Woji!” Mark moaned, louder and louder. “Woji! Woji!” He doubted anyone was still asleep. “Woji says go back! Woji says go back!” He kept his voice hollow, muffled by his hand over his mouth. He repeated the words many times, and ended each message with a thin, rising moan. After a time he added one more word. “Danger. Danger. Danger.”

He stopped abruptly in the middle of the fourth “Danger.” Even he was aware of the listening forest now. The Gary brothers took torches into the forest around the camp, looking for something, anything. They stayed close to one another as they made the search. Most of the boys were sitting up, as close to the fires as they could get. It was a long time before they all lay down to try to sleep again. Mark dozed in the tree, and when he jerked awake, he repeated the warning, again stopping in the middle of a word, though he wasn’t certain why that was so much worse than just stopping. Again the futile search was made, the fires were replenished, the boys sat upright in fear. Toward dawn when the forest was its blackest Mark began to laugh a shrill, inhuman laugh that seemed to echo from everywhere at once.

The next day was cold and drizzly with thick fog that lifted only slightly as the day wore on. Mark circled the straggling group, now whispering from behind them, now from the left, the right, from in front of them, sometimes from over their heads. By midafternoon they were barely moving and the boys were talking openly of disobeying Gary and returning to Washington. Mark noted with satisfaction that two of the Gary brothers were siding with the rebellious boys now.

“Ow! Woji!” he wailed, and suddenly two groups of the boys turned and started to run. “Woji! Danger!”

Others turned now and joined the flight, and Gary shouted at them vainly, and then he and his brothers were hurrying back the way they had come.

Laughing to himself, Mark trotted away. He headed west, toward the valley.

Bruce stood over the bed where the boy lay sleeping. “Is he going to be all right?”

Bob nodded. “He’s been half awake several times, babbling about snow and ice most of the time. He recognized me when I examined him this morning.”

Bruce nodded. Mark had been sleeping for almost thirty hours. Physically he was out of danger, and probably hadn’t been in real danger at all. Nothing rest and food couldn’t cure anyway, but his babblings about the white wall had sounded insane. Barry had ordered everyone to leave the boy alone until he awakened naturally. Barry had been with him most of the time, and would return within the hour. There was nothing anyone could do until Mark woke up.

Later that afternoon Barry sent for Andrew, who had asked to be present when Mark began to talk. They sat on either side of the bed and watched the boy stir, rousing from the deep sleep that had quieted him so thoroughly that he had appeared dead.

Mark opened his eyes and saw Barry. “Don’t put me in the hospital,” he said faintly, and closed his eyes again. Presently he opened his eyes and looked about the room, then back to Barry. “I’m in the hospital, aren’t I? Is anything wrong with me?”

“Not a thing,” Barry said. “You passed out from exhaustion and hunger, that’s all.”

“I would like to go to my own room then,” Mark said, and tried to rise.

Barry gently restrained him. “Mark, don’t be afraid of me, please. I promise you I won’t hurt you now or ever. I promise that.” For a moment the boy resisted the pressure of his hands, then he relaxed. “Thank you, Mark,” Barry said. “Do you feel like talking yet?”

Mark nodded. “I’m thirsty,” he said. He drank deeply. He began to describe his trip north. He told it completely, even how he had frightened Gary and his brothers and routed the expedition to Philadelphia. He was aware that Andrew tightened his lips at that part of the story, but he kept his eyes on Barry and told them everything.

“And then you came back,” Barry said. “How?”

“‘Through the woods. I made a raft to cross the river.” Barry nodded. He wanted to weep, and didn’t know why. He patted Mark’s arm. “Rest now,” he said. “We’ll get word to them to stay in Washington until we dig up some radiation detectors.”

“Impossible!” Andrew said angrily outside the door. “Gary was exactly right in pressing on to Philadelphia. That boy destroyed a year’s training in one night.”

“I’m going too,” Barry had said, and he was with Mark now in Washington. Two of the younger doctors were also with them. The young expedition members were frightened and disorganized; the work had come to a stop, and they had been waiting in the main building for someone to come give them new instructions.